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User
Manual
IR Marker placement
For analysis of AOA’s at distances between 1-2 meters (3.3-6.6 feet) from the participant (optimal distance for IR
Markers), it’s recommended to mount IR Markers on the AOA at a minimum of 10 centimeters apart from each
other. If a participant gets closer (<1 meter or <3.3 feet) to the AOA, the IR Markers may drop from view of the IR
Marker sensor and scene camera. In these situations make sure to have at least 4 extra markers closer together in
the center of the AOA with a minimum distance of 10 centimeters apart to still be able to aggregate data from this
distance, provided 4 IR Markers are still within the field of view of the glasses. Read about Tobii Glasses field of view
and IR Markers on the next page. The minimum distance at which IR Markers can be used is about 60cm, at closer
distances detection will get less robust, which can cause data to not be mapped correctly on a Snapshot.
IR Marker range
The IR Markers have a limited range. The smallest IR Marker detection range (using the minimum size AOA: 4 IR
Markers, at 10cm/4 inches apart is shown below). This minimum detection range can be widened by adding pairs of
IR Markers next to, above, or below the current AOA. Add a set of at least 4 extra IR Markers pointing outwards (not
in one line) to increase the angle of detection. The maximum range will still remain 2.5 meters (8.2 feet).
Distance guidelines for IR Marker detection:
Max. distance: 2.5 meter (8.2 feet) at a 0 degree angle
Minimum distance: 60 centimeters (2 feet).
At least 4 IR Markers should always be within view of
the IR Marker Sensor or Scene camera.
With an AOA to the left of the participant the angle of
detection will be greater than if it was to the right. This
is due to the IR sensor being built in the right side of
the glasses.
1m
1.5m
2m
0.5m
2.5m
0 deg
22.5 deg
45 deg
67.5 deg
10cm
1 2
3 4
AOA
IR Marker
Detection range
Set of 4
IR Markers
Participant
with Tobii Glasses
In range
Edge of range
Out of range
Using IR Markers
IR Marker reference point
IR Marker/AOA plane
IR Marker top view
IR Marker side view
Mounting surface
Mounting IR Markers
IR Markers can be placed in almost any position (e.g. upside down, sideways, angled), as long as the front is facing
the participant and the IR Marker reference points (measured from the IR illuminator) stay on the same plane (see
the image below). Place the IR Markers at an angle pointing towards the glasses worn by a participant to improve
the tracking of IR Markers by Tobii Glasses.
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